Bitumen

Bitumen is an inflammable mineral substance, a black viscous mixture of hydrocarbons, presumably of vegetable origin. It is called Naphtha when liquid and light-coloured, Petroleum when less fluid and darker, Maltha when viscid, and Asphalt when solid. It is obtained either naturally or as a residue from petroleum distillation, and is used chiefly in roofing or surfacing roads. Formerly, it was also used as mortar to fill the gaps between blocks and bind them together in walls and other construction works.